Washington - Doctors examining US Vice President Dick Cheney discovered an abnormal rhythm in his heart Wednesday and ordered him to undergo treatment, the White House said.

Cheney has cancelled plans to attend a campaign event in Illinois to go to George Washington University Hospital for the outpatient procedure involving an electrical impulse to restore a normal rhythm in his heart's upper chamber, Cheney spokeswoman Megan Mitchell said.

Cheney, 67, has a history of heart problems and suffered from four heart attacks beginning in his thirties. The final one occurred in 2000.

Cheney was diagnosed with a similar problem in November and received an electronic jolt to correct the rhythm. He has worn a pacemaker since 2000 and is regularly checked by his doctors. (dpa)